The genus Populus includes various species of trembling aspen, cottonwood, big tooth aspen, balm-of-gilead, white poplar and lombardy poplar. Many aspen trees are grown as forest trees, but aspen trees are also frequently planted in windbreaks, parks, and home landscapes.
This variety of Populus tremuloides (Michx.) has been selected because of a combination of several desirable characteristics, including rapid growth, good tree form, aesthetic qualities, and resistance to Hypoxylon canker caused by the fungus Hypoxylon mammatum.
All known varieties of aspen are quite susceptible to canker disease caused by infection with the fungus Hypoxylon mammatum. However, the cultivar described herein has exhibited good resistance to Hypoxylon mammatum, with calluses forming at the margins of cankers which slow or completely stop the canker growth.
This variety was selected as a ramet from a superior aspen clone growing in an aspen stand in Block 70 of the Pike Bay Experimental Forest on the Chippewa National Forest, near Cass Lake, Cass County, Minn. Root cuttings were taken in 1965 and individual trees were planted at the Rosemount Agricultural Experiment Station, Rosemount, Minn. in 1968 and at the Oconto Seed Orchard on the Nicollet National Forest, Langlade, Wis. in 1971. The trees were planted at a spacing of 10.times.10 meters which enhances canker infection and provides greater selection pressure to identify resistant trees. Several times each growing season, observations have been made of these plantings of the variety with respect to growth, form, resistance to disease and resistance to insects.
The variety described herein has continued to exhibit a novel combination of characteristics, including rapid growth, good form and aesthetic appearance, and most notably a good resistance to canker disease caused by infection from the fungus Hypoxylon mammatum.